金黄色葡萄球菌对临床常用抗菌药物的敏感性及毒力基因检测分析

Analysis in sensitivity and virulence gene detection of Staphylococcus aureus to frequently-used antibiotics in clinical practice

  • 摘要:
      目的  分析金黄色葡萄球菌(简称金葡菌)对临床常用抗菌药物的敏感性及毒力基因检测结果。
      方法  分离金葡菌129株行药敏试验,金葡菌分离自胸腹水、脑脊液及血液等无菌体液标本中,万古霉素等常用抗菌药物对金葡菌的最低抑菌浓度(MIC)采用琼脂稀释法检测,耐甲氧西林金葡菌(MRSA)内耐药基因mecC、mecA和毒力基因sasX与杀白细胞毒素(PVL)基因采用聚合酶链反应(PCR)检测。
      结果  苯唑西林琼脂稀释结果显示,70株为MRSA,其余59株为甲氧西林敏感金葡菌(MSSA);对临床分离所得的45株MRSA分别采用mecA、mecC基因的PCR引物进行PCR扩增,mecA阳性检出率为100.00%,sasX基因阳性检出率为46.67%(21/45),sasX基因阴性检出率为53.33%(24/45),mecC、PVL均未检出;MRSA对β内酰胺类药物的耐药率高于MSSA,且对左氧氟沙星、阿米卡星、庆大霉素等非β内酰胺类药物也有耐药性,但75.00%以上MRSA对甲氧苄啶与利福平比较敏感。MSSA对β内酰胺类药物和非β内酰胺类药物均比较敏感,耐药率均低于11.00%;sasX阴性或sasX阳性的MRSA对左氧氟沙星、磷霉素和β内酰胺类抗生素均比较耐药,但sasX阴性基因与sasX阳性基因对甲氧苄啶、利福平、阿米卡星及庆大霉素的耐药率不完全一致。
      结论  MRSA对临床大多数抗菌药物均有耐药性,临床需对MRSA加强监测。

     

    Abstract:
      Objective  To analyze the sensitivity and results of virulence gene detection of Staphylococcus aureus to frequently-used antibiotics in clinical practice.
      Methods  Totally 129 isolated strains of Staphylococcus aureus from sterile body fluid samples of pleural effusion, ascites, cerebrospinal fluid and blood were prepared for drug sensitivity test. The minimum inhibitory concentration (MIC) of frequently-used antibiotics such as vancomycin to Staphylococcus aureus was detected by agar dilution method. Polymerase chain reaction (PCR) was used to detect endoresistant genes of mecC and mecA, virulence gene of sasX and panton-valentine leukocidin (PVL) gene in methicillin-resistant Staphylococcus aureus (MRSA).
      Results  The dilution of oxacillin agar showed that there were 70 strains of MRSA and 59 strains of methicillin-sensitive Staphylococcus aureus (MSSA). The PCR primers of genes of mecA and mecC for 45 strains of isolated MRSA in clinic showed that positive detection rate of mecA was 100.00%, the positive detection rate of sasX was 46.67%(21/45), the negative detection rate of sasX was 53.33%(24/45), and mecC as well as PVL were not detected. MRSA showed a higher drug resistance rate to β amides and certain drug resistance to non β amides such as levofloxacin, amikacin and gentamicin, but more than 75.00% of MRSA were sensitive to trimethoprim and rifampicin. MSSA were sensitive to both β amides and non β amides, and the drug resistance rate was lower than 11.00%; MRSA with negative or positive sasX were resistant to antibiotics such as levofloxacin, fosfomycin and β amides, but the drug resistance rates of sasX negative genes and sasX positive genes to trimethoprim, rifampicin, amikacin and gentamicin were not completely consistent.
      Conclusion  MRSA is resistant to most antibiotics in clinic, so it is necessary to strengthen the monitoring of MRSA in clinic.

     

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